The short answer
Thymosin beta-4 is the whole protein; TB-500 is a 7-amino-acid fragment of it (residues 17–23), the stretch that binds actin. In animal studies the whole protein speeds tissue repair and supports new blood vessel growth, and it carries signals the fragment lacks. TB-500 runs with a twice-weekly loading phase; full thymosin beta-4 is taken weekly, in shorter cycles.
Side by side
| Compared | TB-500 | Thymosin Beta-4 |
|---|---|---|
| Category | Healing & recovery | Healing & recovery |
| Also known as | Thymosin Beta-4 Fragment, TB4 | Tβ4, Full TB4 |
| What it is | A fragment of thymosin beta-4, a protein your body uses for cell repair. | The full-length version of the protein TB-500 is cut from. |
| How it works | Synthetic fragment of Thymosin Beta-4: Ac-LKKTETQ, the 7-amino-acid stretch (residues 17–23) that binds actin. The whole protein holds actin building blocks back from forming filaments, a reserve cells draw on when they move. In lab and rodent studies the fragment drew blood-vessel cells, sped wound repair in aged mice and strengthened repaired tendons in rats; the anti-inflammatory findings are for the whole protein. Loading phase 2x/week then drop to maintenance. | Full-length Thymosin Beta-4 (as opposed to the TB-500 fragment). In cell and animal studies it promotes tissue repair, angiogenesis and cell survival. Regulates actin dynamics and plays a role in embryonic development and wound healing. |
| Commonly reported | Stubborn soft-tissue injuries loosening up, with range of motion returning over a few weeks. Its own research is a few animal studies; the human trials tested the whole protein. Often paired with BPC-157. | Less nagging joint and soft-tissue pain and stiffness over a few weeks, and sometimes tiredness for a day after injecting. Its human trials are small eye-drop and skin-gel studies; injected use for injuries hasn't been tested in people. |
| Studied range | Research range: 1–2.5 mg. Studied in research — not a recommendation. | Research range: 2–2.5 mg. Studied in research — not a recommendation. |
| How often | 2x/week loading, 1–2mg/week maintenance | Weekly |
| Half-life | ~0.5–2 hours (measured for the whole protein, thymosin beta-4, given IV to healthy volunteers; TB-500 itself has never been measured in people) | ~0.5–2 hours (given IV to healthy volunteers) |
| Route | SubQ injection, IM injection | SubQ injection, IM injection |
| Typical run | Loading phase 2x/week for 4–6 weeks, then maintenance 1x/week or stop. Common to cycle 6–8 weeks on, time off. | Shorter cycles than TB-500 typical — 4–6 weeks. Less community data than TB-500 fragment. |
| Evidence | Emerging: primarily preclinical / limited human data | Emerging: primarily preclinical / limited human data |
| Common side effects | Injection site reaction, fatigue, nausea, headache, lethargy | Injection site reaction, fatigue, headache |
- Category
- TB-500Healing & recovery
- Thymosin Beta-4Healing & recovery
- Also known as
- TB-500Thymosin Beta-4 Fragment, TB4
- Thymosin Beta-4Tβ4, Full TB4
- What it is
- TB-500A fragment of thymosin beta-4, a protein your body uses for cell repair.
- Thymosin Beta-4The full-length version of the protein TB-500 is cut from.
- How it works
- TB-500Synthetic fragment of Thymosin Beta-4: Ac-LKKTETQ, the 7-amino-acid stretch (residues 17–23) that binds actin. The whole protein holds actin building blocks back from forming filaments, a reserve cells draw on when they move. In lab and rodent studies the fragment drew blood-vessel cells, sped wound repair in aged mice and strengthened repaired tendons in rats; the anti-inflammatory findings are for the whole protein. Loading phase 2x/week then drop to maintenance.
- Thymosin Beta-4Full-length Thymosin Beta-4 (as opposed to the TB-500 fragment). In cell and animal studies it promotes tissue repair, angiogenesis and cell survival. Regulates actin dynamics and plays a role in embryonic development and wound healing.
- Commonly reported
- TB-500Stubborn soft-tissue injuries loosening up, with range of motion returning over a few weeks. Its own research is a few animal studies; the human trials tested the whole protein. Often paired with BPC-157.
- Thymosin Beta-4Less nagging joint and soft-tissue pain and stiffness over a few weeks, and sometimes tiredness for a day after injecting. Its human trials are small eye-drop and skin-gel studies; injected use for injuries hasn't been tested in people.
- Studied range
- TB-500Research range: 1–2.5 mg. Studied in research — not a recommendation.
- Thymosin Beta-4Research range: 2–2.5 mg. Studied in research — not a recommendation.
- How often
- TB-5002x/week loading, 1–2mg/week maintenance
- Thymosin Beta-4Weekly
- Half-life
- TB-500~0.5–2 hours (measured for the whole protein, thymosin beta-4, given IV to healthy volunteers; TB-500 itself has never been measured in people)
- Thymosin Beta-4~0.5–2 hours (given IV to healthy volunteers)
- Route
- TB-500SubQ injection, IM injection
- Thymosin Beta-4SubQ injection, IM injection
- Typical run
- TB-500Loading phase 2x/week for 4–6 weeks, then maintenance 1x/week or stop. Common to cycle 6–8 weeks on, time off.
- Thymosin Beta-4Shorter cycles than TB-500 typical — 4–6 weeks. Less community data than TB-500 fragment.
- Evidence
- TB-500Emerging: primarily preclinical / limited human data
- Thymosin Beta-4Emerging: primarily preclinical / limited human data
- Common side effects
- TB-500Injection site reaction, fatigue, nausea, headache, lethargy
- Thymosin Beta-4Injection site reaction, fatigue, headache
Typical run: Community practice — opinions vary. Not a clinical recommendation.
Week by week
Each entry’s cards by day window, as the compound pages show them. Day 1 is the day you start it.
TB-500
- Day 1–7 Week one: set your baseline
- Day 7–14 Stiffness often starts to ease
- Day 14–28 Load tolerance often picks up
- Day 28–42 Gains slow, repair keeps going
- Day 42–56 Weeks 6 to 8: how far it's come
Thymosin Beta-4
- Day 1–14 The full protein, not the fragment
- Day 14–28 Weeks 2 to 4: how the injury responds
Questions people ask
How long do TB-500 and Thymosin Beta-4 last?
The half-life of TB-500 is ~0.5–2 hours (measured for the whole protein, thymosin beta-4, given IV to healthy volunteers; TB-500 itself has never been measured in people). The half-life of Thymosin Beta-4 is ~0.5–2 hours (given IV to healthy volunteers).
How often are TB-500 and Thymosin Beta-4 taken?
TB-500: 2x/week loading, 1–2mg/week maintenance. Routes: SubQ injection, IM injection. Thymosin Beta-4: weekly. Routes: SubQ injection, IM injection.
How are TB-500 and Thymosin Beta-4 dosed in research?
The research range for TB-500 is 1–2.5 mg. The research range for Thymosin Beta-4 is 2–2.5 mg. Studied in research — not a recommendation.
What are the common side effects of TB-500 and Thymosin Beta-4?
For TB-500, the library lists: injection site reaction, fatigue, nausea, headache, lethargy. For Thymosin Beta-4: injection site reaction, fatigue, headache.
Each one in full
PepVault for iPhone
Track either one in PepVault
Log every dose of TB-500 or Thymosin Beta-4, with reminders on your schedule. 7 days free on the yearly plan for new subscribers.
